Single nozzle direct injection system for rapidly variable gasoline/anti-knock agent mixtures

Abstract

Engine management system for operation of a direct injection spark ignition gasoline engine. The system includes a gasoline engine, a source of gasoline and a source of an anti-knock agent. Gasoline and anti-knock agent are introduced into a proportioning valve that delivers a selected mixture of gasoline/anti-knock agent to a high pressure pump. At least one injector receives the selected mixture from the high pressure pump and delivers the mixture into a cylinder of the engine. The engine management system provides a rapidly variable mixture of directly injected anti-knock agent and gasoline which prevents knock as the engine torque increases.

1 . Engine management system for operation of a direct injection spark ignition gasoline engine comprising:
 a gasoline engine;   a source of gasoline;   a source of anti-knock agent;   a first low pressure pump for pumping gasoline from the source of gasoline;   a second low pressure pump for pumping anti-knock agent from the source of anti-knock agent;   a proportioning valve for receiving gasoline and anti-knock agent from the first and second low pressure pumps and delivering a selected mixture of gasoline/anti-knock agent to a high pressure pump; and   at least one injector for receiving the selected mixture from the high pressure pump and directly delivering the liquid mixture into a cylinder of the engine where the ratio of the anti-knock agent to gasoline is sufficient to prevent knock as the torque is increased.   
   
   
       2 . The system of  claim 1  wherein the proportioning valve is driven by an actuator to control the ratio of gasoline to anti-knock agent in the mixture. 
   
   
       3 . The system of  claim 2  wherein the actuator uses rotation or translation to select the mixture. 
   
   
       4 . The system of  claim 1  wherein the anti-knock agent is ethanol. 
   
   
       5 . The system of  claim 1  wherein the anti-knock agent is methanol. 
   
   
       6 . The system of  claim 1  designed with decreased volumes downstream from the proportioning valve. 
   
   
       7 . The system of  claim 1  where the torque is decreased during the fuel-composition adjustment period in order to prevent knock. 
   
   
       8 . The system of  claim 1  further including operating with spark retard or increased spark retard during a fuel-composition adjustment delay period. 
   
   
       9 . The system of  claim 1  or  8  wherein spark retard is increased relative to a spark retard that varies according to a speed/load condition in order to minimize consumption of the anti-knock agent. 
   
   
       10 . The system of  claim 1  further including operating during the fuel-composition adjustment delay period under conditions away from stoichiometry, either with fuel rich or with fuel lean conditions. 
   
   
       11 . The system of  claim 8  or  9  where in addition to spark retard the engine is operated away from stoichiometry, with either rich or lean mixtures. 
   
   
       12 . The system of  claim 1  wherein the high pressure pump and proportioning valve form a single unit. 
   
   
       13 . The system of  claim 1  further including a common rail fuel system with minimized volume. 
   
   
       14 . The system of  claim 1  wherein in the anti-knock agent contains a substantial fraction of ethanol. 
   
   
       15 . The system of  claim 14  wherein the anti-knock agent is E85. 
   
   
       16 . The system of  claim 14  wherein the substantial fraction is on the order of 50% or greater. 
   
   
       17 . The system of  claim 1  wherein the anti-knock agent is an ethanol/water mixture. 
   
   
       18 . The system of  claim 1  wherein the injector is corrosion resistant. 
   
   
       19 . The system of  claim 1  further including a pulse width modulation controller. 
   
   
       20 . The system of  claim 1  further including port fuel injection of gasoline from the source of gasoline during part of the engine operation time. 
   
   
       21 . The system of  claim 20  wherein the direct injector system is primed with the anti-knock agent when the gasoline is being port fuel injected. 
   
   
       22 . The system of  claim 21  where when the anti-knock agent is needed, the direct injector initially injects substantially only the anti-knock agent. 
   
   
       23 . The system of  claim 1  further including an expert system having a microprocessor to anticipate a need for direct injection of the anti-knock agent when the system also operates with PFI injector of gasoline. 
   
   
       24 . Engine management system for operation of a direct injection spark ignition gasoline engine comprising:
 a gasoline engine;   a source of gasoline;   a source of anti-knock agent;   a first low pressure pump for pumping gasoline from the source of gasoline;   a second low pressure pump for pumping the anti-knock agent from the source of anti-knock agent;   a high pressure pump for receiving the gasoline and anti-knock agent and pressurizing them separately;   a proportioning valve for receiving the pressurized gasoline and anti-knock agent and delivering a selected mixture of gasoline and anti-knock agent to at least one injector for direct injection into a cylinder of the engine wherein the ratio of the anti-knock agent to gasoline is sufficient to prevent knock as the torque increases.   
   
   
       25 . The system of  claim 24  wherein the high pressure pump pressurizes the gasoline and anti-knock agent using a single pump shaft. 
   
   
       26 . The system of  claim 3  wherein the proportioning valve includes two limits, the first limit in which the anti-knock agent passage is open but gasoline is closed, and a second limit in which gasoline passage is open but the anti-knock agent passage is closed. 
   
   
       27 . The system of  claim 24  wherein the volume between the high pressure pump and the fuel injectors is minimized to improve transient performance. 
   
   
       28 . The system of  claim 24  wherein the high pressure pump has two vanes for separate pressurization of the anti-knock agent and gasoline. 
   
   
       29 . The system of  claim 1  or  24  wherein total fuel introduced into a cylinder is determined by pulse width modulation of the injector. 
   
   
       30 . The system of  claim 1  or  24  wherein total fuel introduced into a cylinder is partially determined by the pressure of operation of the high pressure pump. 
   
   
       31 . The system of  claim 1  or  24  that can operate either only on gasoline or on the anti-knock agent if the other fuel has been exhausted or is close to exhaustion. 
   
   
       32 . The system of  claim 5  or  24  wherein the anti-knock agent is a methanol containing fuel such as M80 wherein the content of methanol in the anti-knock agent is on the order of 50%. 
   
   
       33 . The system of  claim 24  where the anti-knock agent is ethanol. 
   
   
       34 . The system of  claim 24  further including a single injector with a single nozzle having multiple valves and wherein anti-knock agent and gasoline are mixed in the body of the injector. 
   
   
       35 . The system of  claim 24  wherein the anti-knock agent and gasoline are provided to the injector through independently controlled common rail systems. 
   
   
       36 . The system of  claim 1  or  24  wherein timing and duration of injection of gasoline and ethanol are independently set. 
   
   
       37 . The system of  claim 1  wherein the anti-knock agent does not contain lubrication additives. 
   
   
       38 . The system of  claim 24  wherein the engine is operated with spark retard during transients requiring an anti-knock/gasoline fraction in which the injected anti-knock agent fraction would be insufficient to control knock because of a fuel-composition adjustment delay. 
   
   
       39 . The system of  claim 24  wherein the engine is operated with increased spark retard during transients when the delayed injected anti-knock agent fraction would be insufficient to control knock because of the delay in charging the delivered ethanol fraction. 
   
   
       40 . The system of  claim 24  wherein the engine is operated away from stoichiometric conditions, with either fuel rich or fuel lean conditions during the fuel-composition adjustment delay period. 
   
   
       41 . The system of  claim 38  or  39  wherein the engine is operated away from stoichiometric conditions, with either fuel rich or fuel lean conditions. 
   
   
       42 . The system of  claim 1  or  claim 24  wherein during part of a drive cycle gasoline is port fuel injected. 
   
   
       43 . The system of  claim 1  or  claim 24  wherein port fuel injection alone is used at low torque values when direct injection is not needed for knock control or for emission control. 
   
   
       44 . The system of  claim 1  or  claim 24  wherein the injector first injects only the anti-knock agent from the source of anti-knock agent and over a longer period of time injects gasoline so as to minimize ethanol use while also providing a fast injection ethanol response. 
   
   
       45 . The system of  claim 1  or  claim 24  further including an expert system to anticipate the need for direct injection to prevent knock and wherein the direct injection is started ahead of time to compensate for a lag time in the direct injection fuel delivery system. 
   
   
       46 . The system of  claim 1  further including pulsed pressure air assisted injection to prevent fouling of the injector. 
   
   
       47 . The system of  claim 1  or  24  wherein the injector injects either gasoline, the anti-knock agent or a mix of gasoline and the anti-knock agent during substantially all of the time that the engine is operating. 
   
   
       48 . The system of  claim 10 ,  11 ,  40  or  41  wherein the amount of fuel or air enrichment is determined from the known composition of the anti-knock agent/gasoline fraction in the fuel line, and the amount of turbocharging and torque are adjusted to prevent knock and are lower than desired by the operator until an adequate anti-knock fractional/gasoline fraction is reached. 
   
   
       49 . The system of  claim 24  wherein a pulsed pressure-air-assist injector is used with two secondary PWM valves to control the amount of anti-knock agent and/or gasoline to be injected, allowing for cycle-to-cycle control of the ethanol/gasoline ratio. 
   
   
       50 . The fuel management system of  claim 1  or  24  wherein the injector is integrated with a spark plug. 
   
   
       51 . The fuel management system of  claim 10 ,  11 ,  40  or  41  wherein some of the cylinders operate in fuel rich conditions to avoid knock, while the rest operate on fuel lean conditions to also avoid knock. 
   
   
       52 . The fuel management system of  claim 51  wherein at the catalyst the average air/fuel ratio is close to stoichiometric. 
   
   
       53 . The fuel management system of  claim 51  where a given cylinder operates rich during a portion of the fuel composition adjustment delay, and lean during a different portion of the fuel composition adjustment delay. 
   
   
       54 . The fuel management system of  claim 1  or  24  where the fuel management system records information on the fuel composition in the injection system during engine shutdown, and uses that information for the engine startup from either cold conditions or warm conditions. 
   
   
       55 . The fuel management system of  claim 1  or  24  where the fuel management flushes the fuel injection system downstream from the proportioning valve after initiation of engine shutdown, and introduces gasoline into this region in preparation for engine start-up from either cold conditions or warm conditions. 
   
   
       56 . A fuel management system for a direct injection gasoline engine uses direct injection of an anti-knock agent to prevent knock as the torque is increased comprising:
 A gasoline engine;   A source of gasoline;   A source of the anti-knock agent;   A direct injector with two nozzles wherein one of the nozzles provides gasoline and the other nozzle provides the anti-knock agent and:   wherein a common shaft is used for the direct injection fuel pumps for the gasoline and the anti-knock agent.